Everything. He's the only class with a good chance of soloing terramorphous without cheesing him with the bee/other nefarious activities. He's a bit boring, but he's brilliant at raw damage and keeping his shields up, the only problem is how reliant he is on his turret no matter what tree you use. Still, the turret(s) are a fantastic distraction/roadblock in pretty much every situation.

With no decent melee or elemental options, I can completely understand why some people don't get on with him.